day24

aoc_2024/src/day21.rs

@@ -131,11 +131,9 @@ impl NumButton {
     }
 }
 
-type Input = String;
-
 #[aoc_generator(day21)]
-fn parse(input: &str) -> Input {
+fn parse(input: &str) -> &'static str {
-    input.to_string()
+    unsafe { std::mem::transmute(input) }
 }
 
 type Path = [DistanceSize; 6];
@@ -336,7 +334,7 @@ const CHAR_IDX: [usize; 10] = [
 ];
 
 #[aoc(day21, part1)]
-fn part1(input: &Input) -> DistanceSize {
+fn part1(input: &str) -> DistanceSize {
     let num_paths = const {
         let steps = precompute_steps_new::<2>([[1; 5]; 5]);
         let paths = precompute_paths();
@@ -358,7 +356,7 @@ fn part1(input: &Input) -> DistanceSize {
 }
 
 #[aoc(day21, part2)]
-fn part2(input: &Input) -> DistanceSize {
+fn part2(input: &str) -> DistanceSize {
     let num_paths = const {
         let steps = precompute_steps_new::<25>([[1; 5]; 5]);
         let paths = precompute_paths();
@@ -385,10 +383,10 @@ mod tests {
 
     #[test]
     fn part1_example() {
-        assert_eq!(part1(&parse("379A")), 64 * 379);
+        assert_eq!(part1(parse("379A")), 64 * 379);
-        assert_eq!(part1(&parse("179A")), 68 * 179);
+        assert_eq!(part1(parse("179A")), 68 * 179);
-        assert_eq!(part1(&parse("456A")), 64 * 456);
+        assert_eq!(part1(parse("456A")), 64 * 456);
-        assert_eq!(part1(&parse("980A")), 60 * 980);
+        assert_eq!(part1(parse("980A")), 60 * 980);
-        assert_eq!(part1(&parse("029A")), 68 * 29);
+        assert_eq!(part1(parse("029A")), 68 * 29);
     }
 }

aoc_2024/src/day23.rs

@@ -0,0 +1,233 @@
+use aoc_runner_derive::{aoc, aoc_generator};
+use hashbrown::{HashMap, HashSet};
+
+type Input = (usize, [Vec<usize>; 26 * 26], HashMap<usize, String>);
+
+#[aoc_generator(day23)]
+fn parse(input: &str) -> Input {
+    let mut i = 0;
+    let mut names = HashMap::new();
+    let mut ids = HashMap::new();
+    let mut adj_list = [const { Vec::new() }; 26 * 26];
+    input.lines().for_each(|line| {
+        let mut splits = line.split('-');
+        let left = splits.next().unwrap().to_string();
+        let right = splits.next().unwrap().to_string();
+
+        let left_id = {
+            *ids.entry(left.clone()).or_insert_with(|| {
+                let id = i;
+                i += 1;
+                names.insert(id, left);
+                id
+            })
+        };
+        let right_id = {
+            *ids.entry(right.clone()).or_insert_with(|| {
+                let id = i;
+                i += 1;
+                names.insert(id, right);
+                id
+            })
+        };
+
+        adj_list[left_id].push(right_id);
+        adj_list[right_id].push(left_id);
+    });
+
+    (i, adj_list, names)
+}
+
+#[aoc(day23, part1)]
+fn part1(input: &Input) -> usize {
+    let num = input.0;
+    let adj_list = &input.1;
+    let names = &input.2;
+
+    (0..num)
+        .filter(|id| names[id].starts_with("t"))
+        .flat_map(|id| {
+            let mut three_groups = HashSet::new();
+            let adj = &adj_list[id];
+
+            for left in 0..adj.len() {
+                for right in left + 1..adj.len() {
+                    if adj_list[adj[left]].contains(&adj[right]) {
+                        let mut group = [id, adj[left], adj[right]];
+                        group.sort();
+                        three_groups.insert((group[0], group[1], group[2]));
+                    }
+                }
+            }
+
+            three_groups
+        })
+        .collect::<HashSet<(usize, usize, usize)>>()
+        .into_iter()
+        .count()
+}
+
+#[aoc(day23, part2)]
+fn part2(input: &Input) -> String {
+    let num = input.0;
+    let adj_list = &input.1;
+    let names = &input.2;
+
+    let max_clique = (0..num)
+        .filter(|id| names[id].starts_with("t"))
+        .flat_map(|id| {
+            let mut three_groups = HashSet::new();
+            let adj = &adj_list[id];
+
+            for left in 0..adj.len() {
+                for right in left + 1..adj.len() {
+                    if adj_list[adj[left]].contains(&adj[right]) {
+                        let mut group = [id, adj[left], adj[right]];
+                        group.sort();
+                        three_groups.insert((group[0], group[1], group[2]));
+                    }
+                }
+            }
+
+            three_groups
+        })
+        .collect::<HashSet<(usize, usize, usize)>>()
+        .into_iter()
+        .flat_map(|(a, b, c)| {
+            let clique = vec![a, b, c];
+            expand_cliques(clique, num, adj_list)
+        })
+        .max_by_key(|clique| clique.len())
+        .unwrap();
+
+    let mut names = max_clique
+        .iter()
+        .map(|id| names[id].clone())
+        .collect::<Vec<String>>();
+    names.sort();
+
+    names.join(",")
+}
+
+fn expand_cliques(current: Vec<usize>, num: usize, adj: &[Vec<usize>]) -> Vec<Vec<usize>> {
+    let mut expansions: Vec<Vec<usize>> = vec![current.clone()];
+
+    for node in 0..num {
+        if current.contains(&node) {
+            continue;
+        }
+
+        if !current
+            .iter()
+            .all(|clique_node| adj[*clique_node].contains(&node))
+        {
+            continue;
+        }
+
+        let mut pushed = false;
+        for clique in &mut expansions {
+            if clique
+                .iter()
+                .all(|clique_node| adj[*clique_node].contains(&node))
+            {
+                clique.push(node);
+                pushed = true;
+                continue;
+            }
+        }
+        if !pushed {
+            let mut new_clique = current.clone();
+            new_clique.push(node);
+            expansions.push(new_clique);
+        }
+    }
+
+    expansions
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn part1_example() {
+        assert_eq!(
+            part1(&parse(
+                "kh-tc
+qp-kh
+de-cg
+ka-co
+yn-aq
+qp-ub
+cg-tb
+vc-aq
+tb-ka
+wh-tc
+yn-cg
+kh-ub
+ta-co
+de-co
+tc-td
+tb-wq
+wh-td
+ta-ka
+td-qp
+aq-cg
+wq-ub
+ub-vc
+de-ta
+wq-aq
+wq-vc
+wh-yn
+ka-de
+kh-ta
+co-tc
+wh-qp
+tb-vc
+td-yn"
+            )),
+            7
+        );
+    }
+
+    #[test]
+    fn part2_example() {
+        assert_eq!(
+            part2(&parse(
+                "kh-tc
+qp-kh
+de-cg
+ka-co
+yn-aq
+qp-ub
+cg-tb
+vc-aq
+tb-ka
+wh-tc
+yn-cg
+kh-ub
+ta-co
+de-co
+tc-td
+tb-wq
+wh-td
+ta-ka
+td-qp
+aq-cg
+wq-ub
+ub-vc
+de-ta
+wq-aq
+wq-vc
+wh-yn
+ka-de
+kh-ta
+co-tc
+wh-qp
+tb-vc
+td-yn"
+            )),
+            "co,de,ka,ta"
+        );
+    }
+}

aoc_2024/src/day24.rs

@@ -0,0 +1,303 @@
+use std::collections::VecDeque;
+
+use aoc_runner_derive::{aoc, aoc_generator};
+use hashbrown::{HashMap, HashSet};
+use nom::{
+    bytes::complete::tag,
+    character::complete::{anychar, newline, one_of, space1, u64},
+    multi::{fill, many1, separated_list0},
+    sequence::{delimited, separated_pair},
+    IResult,
+};
+
+type Line = [char; 3];
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum Operation {
+    And,
+    Or,
+    Xor,
+}
+
+#[derive(Debug, Clone, Copy)]
+struct Gate {
+    operation: Operation,
+    in_0: Line,
+    in_1: Line,
+    out: Line,
+}
+
+type Input = (Vec<(Line, u64)>, Vec<Gate>);
+
+#[aoc_generator(day24)]
+fn parse(input: &str) -> Input {
+    separated_pair(
+        separated_list0(newline, separated_pair(parse_line, tag(": "), u64)),
+        tag("\n\n"),
+        separated_list0(newline, parse_instruction),
+    )(input)
+    .unwrap()
+    .1
+}
+
+fn parse_line(input: &str) -> IResult<&str, [char; 3]> {
+    let mut buffer = ['0'; 3];
+    let (input, _) = fill(anychar, &mut buffer)(input)?;
+    Ok((input, buffer))
+}
+
+fn parse_instruction(input: &str) -> IResult<&str, Gate> {
+    let (input, in_0) = parse_line(input)?;
+    let (input, operation) = delimited(space1, many1(one_of("ANDXOR")), space1)(input)?;
+    let (input, in_1) = parse_line(input)?;
+    let (input, _) = tag(" -> ")(input)?;
+    let (input, out) = parse_line(input)?;
+    match operation[0] {
+        'A' => Ok((
+            input,
+            Gate {
+                in_0,
+                in_1,
+                out,
+                operation: Operation::And,
+            },
+        )),
+        'O' => Ok((
+            input,
+            Gate {
+                in_0,
+                in_1,
+                out,
+                operation: Operation::Or,
+            },
+        )),
+        'X' => Ok((
+            input,
+            Gate {
+                in_0,
+                in_1,
+                out,
+                operation: Operation::Xor,
+            },
+        )),
+        _ => unreachable!(),
+    }
+}
+
+#[aoc(day24, part1)]
+fn part1(input: &Input) -> usize {
+    let fixed = &input.0;
+
+    let mut values = HashMap::new();
+
+    for (line, value) in fixed {
+        values.insert(line, *value);
+    }
+
+    let mut gates = VecDeque::new();
+
+    for gate in &input.1 {
+        gates.push_back(gate);
+    }
+
+    while let Some(gate) = gates.pop_front() {
+        if values.contains_key(&gate.in_0) && values.contains_key(&gate.in_1) {
+            let in_0 = values[&gate.in_0];
+            let in_1 = values[&gate.in_1];
+            let out = match gate.operation {
+                Operation::And => in_0 & in_1,
+                Operation::Or => in_0 | in_1,
+                Operation::Xor => in_0 ^ in_1,
+            };
+            values.insert(&gate.out, out);
+        } else {
+            gates.push_back(gate);
+        }
+    }
+
+    values
+        .into_iter()
+        .filter(|(line, value)| line[0] == 'z' && *value == 1)
+        .map(|(line, _)| {
+            1 << line[1..3]
+                .iter()
+                .collect::<String>()
+                .parse::<u64>()
+                .unwrap()
+        })
+        .sum()
+}
+
+#[aoc(day24, part2)]
+fn part2(input: &Input) -> String {
+    let swaps: &[(Line, Line)] = &[
+        (['h', 'm', 't'], ['z', '1', '8']),
+        (['b', 'f', 'q'], ['z', '2', '7']),
+        (['h', 'k', 'h'], ['z', '3', '1']),
+        (['f', 'j', 'p'], ['b', 'n', 'g']),
+    ];
+    // let swaps: &[(Line, Line)] = &[];
+    let mut gates = input.1.clone();
+    for gate in &mut gates {
+        for (from, to) in swaps {
+            if gate.out == *from {
+                gate.out = *to;
+            } else if gate.out == *to {
+                gate.out = *from;
+            }
+        }
+    }
+
+    for gate in &gates {
+        if gate.out[0] == 'z' && gate.operation != Operation::Xor {
+            println!("gate {:?} outputs to a z but is not xor", gate);
+        }
+    }
+
+    let mut c = ['r', 'j', 'r'];
+
+    for bit in 1..=44 {
+        let x = [
+            'x',
+            (bit as u8 / 10 + 48) as char,
+            (bit as u8 % 10 + 48) as char,
+        ];
+        let y = [
+            'y',
+            (bit as u8 / 10 + 48) as char,
+            (bit as u8 % 10 + 48) as char,
+        ];
+
+        let xy_gates = find_gate(&gates, &x, &y);
+
+        assert_eq!(
+            xy_gates.len(),
+            2,
+            "there is not exactly two xy gates {:?}\nrelated gates: {:?}",
+            xy_gates,
+            find_debug_gate(&gates, &x, &y)
+        );
+
+        let line_xy_xor = xy_gates
+            .iter()
+            .find(|g| g.operation == Operation::Xor)
+            .unwrap()
+            .out;
+
+        let line_xy_and = xy_gates
+            .iter()
+            .find(|g| g.operation == Operation::And)
+            .unwrap()
+            .out;
+
+        let xyc_gates = find_gate(&gates, &line_xy_xor, &c);
+
+        assert_eq!(xyc_gates.len(), 2,
+            "there is not exactly two output gates {:?}\nrelated gates: {:?}\nxy_and: {}\nxy_xor: {}",
+            xyc_gates,
+            find_debug_gate(&gates, &line_xy_xor, &c),
+            display_line(&line_xy_and),
+            display_line(&line_xy_xor),
+        );
+
+        let line_xyc_xor = xyc_gates
+            .iter()
+            .find(|g| g.operation == Operation::Xor)
+            .unwrap()
+            .out;
+
+        let line_xyc_and = xyc_gates
+            .iter()
+            .find(|g| g.operation == Operation::And)
+            .unwrap()
+            .out;
+
+        let xyco_gates = find_gate(&gates, &line_xyc_and, &line_xy_and);
+
+        assert_eq!(
+            xyco_gates.len(),
+            1,
+            "there is no or more than one output gate {:?}\nrelated gates: {:?}\nxy_and: {}\nxy_xor: {}\nxyc_and: {}\nxyc_xor: {}",
+            xyco_gates,
+            find_debug_gate(&gates, &line_xyc_and, &line_xy_and),
+            display_line(&line_xy_and),
+            display_line(&line_xy_xor),
+            display_line(&line_xyc_and),
+            display_line(&line_xyc_xor),
+        );
+
+        c = xyco_gates[0].out;
+
+        println!(
+            "for bit {} z-output is {} and carry out is {}",
+            bit,
+            display_line(&line_xyc_xor),
+            display_line(&c)
+        );
+    }
+
+    let mut wires = swaps
+        .iter()
+        .flat_map(|(a, b)| [display_line(a), display_line(b)])
+        .collect::<Vec<String>>();
+
+    wires.sort();
+
+    wires.join(",")
+}
+
+fn display_line(line: &Line) -> String {
+    line.iter().collect()
+}
+
+fn find_gate(gates: &[Gate], in_0: &Line, in_1: &Line) -> Vec<Gate> {
+    gates
+        .iter()
+        .filter(|gate| {
+            (gate.in_0 == *in_0 && gate.in_1 == *in_1) || (gate.in_0 == *in_1 && gate.in_1 == *in_0)
+        })
+        .copied()
+        .collect()
+}
+
+fn find_debug_gate(gates: &[Gate], in_0: &Line, in_1: &Line) -> Vec<Gate> {
+    gates
+        .iter()
+        .filter(|gate| {
+            gate.in_0 == *in_0 || gate.in_1 == *in_1 || gate.in_0 == *in_1 || gate.in_1 == *in_0
+        })
+        .copied()
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn part1_example() {
+        assert_eq!(
+            part1(&parse(
+                "x00: 1
+x01: 1
+x02: 1
+y00: 0
+y01: 1
+y02: 0
+
+x00 AND y00 -> z00
+x01 XOR y01 -> z01
+x02 OR y02 -> z02"
+            )),
+            4
+        );
+    }
+
+    #[test]
+    fn part2_example() {
+        assert_eq!(
+            part2(&parse(include_str!("../input/2024/day24.txt").trim_end())),
+            "z00,z01,z02,z05"
+        );
+    }
+}

aoc_2024/src/lib.rs

@@ -1,3 +1,5 @@
+mod day24;
+mod day23;
 mod day22;
 mod day21;
 mod day1;